Vaccines and Preventable Diseases:

Rotarix® Rotavirus Vaccine: Rare Side Effect Possible
Questions and answers for parents and caregivers

Rotavirus Vaccines Continue to be Recommended for Benefits in Preventing Serious Rotavirus Disease among U.S. Infants and Children.

Summary

• A safety monitoring study of Rotarix rotavirus vaccine conducted in Mexico by the vaccine’s manufacturer, GlaxoSmithKline, suggests that Rotarix vaccine may cause intussusception in infants during the first week after they receive the first dose of the vaccine. Intussusception is a type of bowel blockage caused when the bowel folds into itself like a telescope.
• If the risk for U.S. infants is similar to that found in the Mexico study, it would translate to 0 to 4 cases of intussusception from vaccine per 100,000 U.S. infants who receive the first dose of Rotarix.
• Rotavirus vaccines offer tremendous benefits by protecting infants and children from rotavirus disease. Rotavirus is the most common cause of severe diarrhea among infants and young children.
• The risk of intussusception after rotavirus vaccination is much lower than the risk of severe rotavirus disease in U.S. children who do not receive rotavirus vaccine.
• In addition to Rotarix, there is a second rotavirus vaccine available in the United States, RotaTeq, made by Merck
• CDC continues to recommend both of these vaccines to prevent rotavirus disease.

When my infant receives rotavirus vaccine, what should I watch for in case there is a side effect?

Most babies who get rotavirus vaccine have no problems with it. Babies are slightly more likely to be irritable, or to have mild, temporary diarrhea or vomiting after a dose of rotavirus vaccine.

Some data suggest a small increase in intussusception cases during the first week after getting the first dose of rotavirus vaccine. The risk is estimated to be 0 to 4 cases of intussusception out of 100,000 infants.

During the first week after the first dose of vaccine, if your baby develops episodes of stomach pain with severe crying (which may be brief), several episodes of vomiting, blood in the stool, or acts weak or very irritable, you should contact a doctor promptly and tell them your infant recently received rotavirus vaccine.

There are good doctors and hospitals in my area, so why should I use rotavirus vaccine to prevent my child from getting rotavirus disease if the vaccine may cause intussusception?

The risk of intussusception found in the Mexico study is much lower than the risk of severe rotavirus disease in U.S. children who do not receive rotavirus vaccine. Rotavirus vaccines offer tremendous benefits by protecting children from rotavirus disease. Rotavirus is the most common cause of severe diarrhea among infants and young children.

Before use of rotavirus vaccines, almost every U.S. child became infected with rotavirus before 5 years of age. U.S. children faced significant risks from rotavirus disease:

• 1 child out of every 70 children was hospitalized
• 1 child out of every 17 children went to a hospital emergency department

In the United States before rotavirus vaccination was available, an estimated 20 to 60 children died because of rotavirus disease each year.

Click to view more information on rotavirus symptoms...

Infants and children with rotavirus disease usually suffer watery diarrhea for 3 to 8 days, and vomiting and fever are common. Young children may lose interest in eating and drinking and become dehydrated because they do not take in enough fluids. In severe cases, children need to go to the hospital to receive fluids given directly into a vein using an intravenous line (IV).

Has rotavirus vaccine had a positive impact in the United States?

The rotavirus vaccination program has had remarkable success in the United States. A U.S. study showed that RotaTeq vaccine was more than 80% effective in preventing severe rotavirus disease in vaccinated infants and young children. In addition, the number of U.S. children hospitalized or brought to the emergency department because of rotavirus disease has gone down by about 85% since the vaccines have been in use.

Does this new information mean that RotaTeq rotavirus vaccine is safer than Rotarix rotavirus vaccine?

The information available does not demonstrate an increased risk of intussusception with RotaTeq. However, the data available cannot rule out a risk of intussusception with RotaTeq as low as the risk currently reported with Rotarix in the Mexico study. Studies are ongoing.

Click to view more information on vaccine safety monitoring...

In the United States, vaccine safety is constantly monitored using the Vaccine Adverse Event Reporting System (VAERS), co-sponsored by CDC and the FDA. VAERS collects and analyzes reports of adverse events (possible side effects) that happen after vaccination. VAERS is an early warning system to alert researchers to possible side effects, but the system is not set up to determine whether reported events are actually associated with receiving a particular vaccine.

Other types of studies can answer this question. The Vaccine Safety Datalink (VSD), a network of 8 managed care organizations with data for more than 9 million people, is often used for such studies.

According to VAERS, an increased risk of intussusception may be possible in the first week after receiving the first dose of RotaTeq. A VSD study is being done to see if RotaTeq is associated with intussusception. It includes data on more than 800,000 total doses of the vaccine. This study has not found a risk of intussusception. However, the VSD study cannot rule out a risk of intussusception with RotaTeq as low as the risk currently reported with Rotarix in the Mexico study.

Why is this information coming out now?

This new information is the result of planned safety monitoring that has been ongoing since the rotavirus vaccines available today were approved for use in the United States.

Click to view more information on pre-approval studies of rotavirus vaccines...

Intussusception was a side effect of the first rotavirus vaccine available in the United States, and that vaccine is no longer available. It was estimated to cause intussusception in 1 infant out of every 10,000 infants who received it.

For the two new rotavirus vaccines in the United States, large studies were conducted before approval to make sure that they did not have this level of risk. In each of these pre-approval studies, about 30,000 – 35,000 infants were given rotavirus vaccines. Both new vaccines were approved by FDA because these studies showed them to be safe and effective, and these studies did not show an increase in the risk of intussusception.

However, even large safety studies may not always be able to detect events that happen rarely. Ongoing studies are done to gather more and more information as the vaccines are being used. For rotavirus vaccines, these studies make it possible to determine if the vaccines have a risk of intussusception that may have been too low to detect in the studies done before vaccine approval. CDC, FDA, and the manufacturers are committed to conducting these ongoing studies.

Rotarix vaccine has been available in the United States since 2008. About 2.7 million doses have been distributed. There are not enough safety data from ongoing studies in the United States to allow researchers to detect a level of risk as low as the one found in the Mexico study. The manufacturer, as well as CDC and FDA, are monitoring the safety of this vaccine in the United States.

When should children get rotavirus vaccine?

Rotavirus vaccines are approved for use only among infants, and not among children and adolescents.

• For one brand of vaccine (RotaTeq), infants should receive three doses of vaccine, one at ages 2, 4, and 6 months.
• For the other brand of rotavirus vaccine (Rotarix), infants should receive two doses of vaccine, one at ages 2 and 4 months.

Click to view more information on recommended ages for rotavirus vaccine...

The first dose may be given as early as 6 weeks of age, and should be given by age 14 weeks 6 days. The last dose should be given by 8 months of age.

 

For more on intussusceptions, see Questions & Answers about Intussusception.

For information from the U.S. Food and Drug Administration, including changes to the label for Rotarix, go to FDA: Rotarix.

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